The present invention relates to chair structures and, more particularly, to chair structures made more comfortable to sit.
Presently, there exist chairs generally having a backrest or seat portion provided with cloth to be used at offices, campsites or the like. Such a chair is constructed by using a metal pipe frame to form an outer edge of the backrest or seat portion and sewing cloth directly on the frame.
With such a pipe frame directly attached with cloth, however, sitting comfort of the chair is subject to the elastic force of the cloth. Accordingly, use of hard cloth to impart the backrest or seat portion with a certain strength raises a problem that the sitting comfort of the chair becomes worse due to a lowered elastic force in the direction against which the back of a sitting person leans.
Further, since such a chair comprises a pipe frame or a wood frame to which cloth is directed attached, the chair involves another problem that a steep step is defined at the boundary between the pipe frame or wood frame and the cloth when a person sits on the chair and, hence, such a step gives the sitting person an uncomfortable feeling.
The present invention has been made in view of the foregoing problem, and it is an object of the present invention to provide a chair using an upholstery member in which a contacting portion of a seat or backrest portion is imparted with elasticity to offer better sitting comfort.
It is another object of the present invention to provide a chair offering a better contact feeling at around a portion attached with an upholstery member.
Accordingly, the present invention provides a chair fitted with an upholstery member in a portion adapted to contact a human body, wherein: an elastic member is provided which allows a deflection in a direction in which a load imposed by the human body contacting the chair works; and the upholstery member is mounted over the elastic member.
The construction in which the upholstery member is mounted over the elastic member allowing a deflection in the load working direction makes it possible to have the chair offer a soft sitting comfort by virtue of the elastic force resulting from the deflection of the elastic member even if the elastic force of the upholstery member is small.
Such an elastic member may be disposed in a seat portion as well as in a backrest portion. The method of mounting the upholstery member over the elastic member may include putting the upholstery member over the elastic member or wrapping the elastic member with the upholstery member.
In such an invention, the elastic member preferably has a fixed end on one side and a free end on other side. With this feature, an elastically restoring force corresponding to the amount of deflection can be gradually varied from the fixed end side of the elastic member thereby offering a smooth sitting comfort.
Particularly where such an elastic member is disposed in a backrest portion, a central portion of the backrest portion can deflect when a person sits on the chair, and with this deflection the head of the sitting person is raised forward about the shoulder portion of the backrest serving as a fulcrum thereby making it possible to direct the eyes of the sitting person at a working area on a desk or the like.
Further, if the free end side of the elastic member is curved toward the direction in which the load imposed by the sitting person works, the upholstery member can deflect smoothly along the curved portion of the elastic member thereby lessening uncomfortable feeling that is given by a portion contacting the human body.
In such a chair, it is possible to attach the elastic member in a manner to press the upholstery member toward the side contacting the human body (i.e., in the direction opposite to the load working direction). With this feature, the upholstery member mounted over the elastic member is pressed from the inside and, hence, wrinkles or the like of the upholstery member can be eliminated.
When such an invention is applied to a chair capable of inclining an upper portion of the backrest portion rearwardly, better sitting comfort can be ensured by the upholstery member, while, even if only the upper portion of the backrest portion is inclined rearwardly, expansion and contraction of the upholstery member due to the rearward inclination can be absorbed by the elastic member deflecting.
According to an invention for attaining the other object, there is provided a chair fitted with an upholstery member disposed in a portion adapted to contact a human body and attached to a frame, wherein: the frame is formed with an escape portion which allows the upholstery member to gradually align with the frame from an attached end of the upholstery member when a load is imposed on the upholstery member.
Since the escape portion allowing the upholstery member to gradually align with the frame is provided, a sharp bend of the upholstery member will not occur and, hence, uncomfortable feeling given by contact with a portion around this bend can be lessened, while at the same time the upholstery member can be prevented from wearing. It is sufficient to provide a curved or inclined portion adjusted to the build and weight of a prospective sitting person. In this case, it is possible to reduce portions contacting the frame as much as possible if a frame formed with such an escape portion is provided at four corners of a human body contacting portion such as the backrest portion or the like.
Preferably, the chair fitted with such an upholstery member comprises a cantilever elastic member attached to the chair, the upholstery member being placed thereover, and an escape space provided on a side allowing deflection of the elastic member, the escape space being widened from the fixed end side to the free end side of the elastic member.
Specifically, in the case where cloth or the like is attached to the seat or backrest portion forming a human body contacting portion, the elastic member is first attached with its one end made free and the other end fixed and then the cloth or the like is placed over the elastic member. In this process the escape space extending from the fixed end to the free end of the elastic member is defined for allowing deflection. With this feature, if the elastic member is composed of a highly deflectable material for example, the elastic member deforms within the escape space, so that the portion contacting the human body will not give an uncomfortable feeling to the sitting person.
If a frame having a curved portion aligning with deflection of the elastic member on the deflection allowing side is provided, the elastic member can be aligned with the curved portion even if the elastic member deflects largely, whereby the portion contacting the human body can be imparted a smooth touch, while at the same time the elastic member can be prevented from deteriorating due to its deflection.